1. Technical Field
The present invention relates to a separating process by liquid chromatography, more particularly an industrial process for separating a large amount of samples by liquid chromatography, and to an apparatus therefor.
2. Prior Art
Liquid chromatography using liquid as a mobile phase is being generally used as an analytical method in various fields since a sample in a very small amount can be readily analyzed rapidly and with high precision and with good reproducibility by this technique. A liquid chromatographic analysis apparatus comprises a liquid transfer part, a sample injecting part, a separating part (column) and a detecting part. In this chromatographic apparatus, a liquid as a mobile phase is previously caused to flow by the liquid transfer part, and a sample is then injected from the injecting part. The components in the sample are eluted in order from those having weaker affinity for the stationary phase to those having stronger affinity therefor. These eluates are detected by the detector for profiling a chromatogram. Applications of analytical liquid chromatography to separation system on an industrial scale only by increasing the diameter of the column have been proposed.
In analytical separation methods using liquid chromatography and analytical apparatuses using the methods, fine particulate packings with a particle size of 5 .mu.m or less are generally used, and a small amount of a sample is loaded thereon. The apparatus is operated under a high pressure of 50 to 100 kg/cm.sup.2, and the small amount of the sample loaded is separated with high precision with a small single column having several ten .mu.m of H.E.T.P. (height equivalent of theoretical plate). On the other hand, separation using liquid chromatography on an industrial scale should be carried out while keeping the required resolving power to separate efficiently objective components taking account of the large amount of load and economy. In other words, it is necessary to separate efficiently a large amount of sample in a large column having a H.E.T.P. of several ten .mu.m or more under a low pressure of 20 kg/cm.sup.2 or less with the use of inexpensive packings having a large particle size of 10 .mu.m or more in place of expensive fine particulate packings. Thus, conventional large-scale separating methods and apparatuses therefor wherein analytical separating methods and apparatuses therefor are only scaled up are not economical or efficient.